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Skilsaw, which is well known for their worm drive circular saws, has recently announced several new products: a dry cutting chop saw, a worm drive metal-cutting saw, and a 10″ worm drive table saw.

Yes, you heard that right, a worm drive portable table saw, which Skilsaw says is the world’s first.

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My knowledge of table saw drive mechanisms is a little limited, but I am under the impression that most if not all portable table saws have direct drive systems. Larger stationary table saws are different, with the better ones having belt-driven blades.

So why should you care?

Worm drive = more power. Or at least that’s true with how worm drive circular saws are more powerful than smaller and more compact sidewinder saws.

The same seems to be true about this saw, as Skilsaw says the worm drive gearing results in maximum torque and power.

The new Skilsaw SPT70WT-22 is said to deliver increased power and durability, and great rip cutting performance and reliability, all while still being portable.

It’s equipped with a Dual Field motor (which Skilsaw says is best in class) for increased cutting speed, cool running, and extended motor life. Rip cutting capacity more than 24″, for breaking down sheets of plywood, and cutting depth is 3-1/2″, for cutting 4x boards in a single pass.

Skilsaw designed the new saw for a wide audience, including carpenters, framers, general contractors, and custom builders.

Structurally, the new Skilsaw worm drive table saw has an all-metal roll cage and die cast aluminum table top. It also features a Smart Guard System which covers the blade and includes anti-kickback functionality.

Even so, this is clearly being marketed as a professional-grade portable table saw, in contrast to the $100 Skil and Skilsaw table saws you might find on special during holiday seasons at your local home improvement store.

Also keep in mind that Skilsaw, and Skil, are Bosch subsidiaries. Bosch, which is soon launching its ReaXX portable table saw, is no newcomer when it comes to professional portable table saws. Although this is the first-ever worm drive portable table saw, I have faith in the companies that they got it right.

I can’t say that I’ve ever heard of users’ desires for a worm drive table saw, but more power, performance, and application speed is always a good thing.

I’m still waiting to hear back about a couple of questions, such as whether it can work with dado blades, but am eager to see what questions you might have. There is also just one image of the new saw, but we’re bugging Skilsaw for more.

If you ask me, I think it’s good to see more fresh technology in a market that could use increases competition and innovation.

If the blade on this saw was to bind and kick due to tension in the lumber being ripped at a depth of 3 1/2 inches, would this “portable” table saw be stable enough to not cause a dangerous situation by shifting it’s position on whatever surface it was resting on? Are there safety features being recommended or supplied to counter a situation like this by the manufacturer?

Interesting. Wonder how the worm drive would affect kickback. Although I’m not sure why no one comes out with a portable European sliding table saw. If done right it could take the place of the contractor table saw and the miter saw.

Nevermind. Apparently Metabo made what I want like 7 years ago but it didn’t come to the US.

I kind of wonder why some of these companies don’t bring over a few of these neat saws and let contractors use them for a short time to get honest feedback as to what they think. How many American people actually have used a European sliding saw for example? If they don’t know it exists then of course they will just keep buying regular table saws.

Reminds me of when the video game Gran Turismo came out. Americans started asking why can’t they get the Mitsubishi Evo and the Subaru WRX. The demand was so much so that both car companies started bringing over both models, all because of a video game. Most Americans didn’t really know about those cars until that game came out.

I would think some of that could be true with some of these tools as well.

I used small Norsaws for years. I could break them down to carry to jobs. I added an extra fence for ~10 of rip fence. Loved it. I sold it because I don’t have shop space and I’ll buy something that’s easier to set up and break down frequently. It was great for panels and ripping. I usually had a chop-saw as well so I didn’t use it for that purpose as much.

I recently bought a Dewalt 7490 because of it’s extension gear drive – the fence stability and the stand. it’s was more than 379 though.

It looks intrigueing but I don’t know that a worm drive really will do that much here. In this case weight, balance and handling don’t matter if the table is stable. They do matter in a hand guided circular saw – this is where worm drive allowed gear reduction, higher torque to go with small faster motor speed and in a more stable package. Thus more power and more managment circular saw – eventally motor design started to get better tuned for useage and non worm drive circular saws caught up.

In a table saw I can’t say it would matter. now on the other hand – frame look alot like the bosch as it should. I’m sure if on a stable stand or base it will cut.

so again the question would be how well does the fence and the extension work?

I really like the idea of this, but it is not clear to me if this is the better system for a portable table saw.

For a DC motor (I have never worked with AC / induction motors so I can’t comment on them), there are a few ways to make it more powerful – the most obvious ways are to make it bigger or to make is spin faster. One can make the motor bigger in one of two ways: make it longer or make the diameter bigger. While making the motor longer does make it more powerful, making it larger in diameter is much more effective at increasing the torque the motor produces – this is fairly intuitive as torque equals force multiplied by the distance at which it acts. So, if you want to make a motor bigger, the best approach is to make the diameter bigger. The other way to get more power from a motor is to spin it faster. This is why Formula one engines (or really any racing internal combustion engine) spin to very high RPMs.

As a way of example, let’s say we have two designs for a theoretical table saw – one with a direct drive and one with a worm drive. One table saw has a large diameter, direct drive DC motor (ie there is no gear train). This motor makes 100 ft-lbs of torque and spins at 1,000 RPM when cutting. Both table saws use a blade of 1 ft radius. For the direct drive table saw, the blade exerts 100 lbs of force on the material being cut (100 ft-lbs of torque / 1 ft radius). For the worm drive table saw, the motor makes 20 ft-lbs of torque, but spins at 10,000 RPM. In order to get the blade speed down to the correct RPM, we need to use a worm drive with 10:1 reduction – this means that although the motor is spinning at 10,000 RPM, the blade spins at 1000 RPM. The advantage of this gear reduction is we multiply the torque by the same ratio, so the torque at the blade is 20 ft-lbs multiplied by the 10X gear ratio for a total of 200 ft-lbs at the blade. Since the blade is the same diameter, the force at the blade is 200 lbs, or twice the force of the direct drive saw. In real life there are efficiency losses through the gear train, and worm gear configurations typically have higher gear train losses than other types, but to first order we can neglect the losses and the math above applies.

The downside to the gear train is that we have a lot more parts (the gear train), and in a worm drive (as opposed to a belt drive) they are all made of metal – so there is a size and weight penalty due to the gear train. On the flip side, the motor is smaller, and all of the important parts of the motor are either made of copper or iron – both of which are very heavy and their amount goes up with the square of the motor diameter. So we traded a big, heavy motor, for a small, fast motor with a worm drive gear train. If the worm drive housing is made of cast iron, we would probably have been better off with a larger diameter motor, but if the housing is made of magnesium, you probably end up with a saw that is more powerful for the same weight – which is why worm drive circular saws have magnesium housings.

I don’t know any of the details of this worm drive table saw, but it has the potential to offer more power in a smaller, lighter package. The engineers could have gotten the same power with a direct drive system, but it is possible that the comparable saw would have been bigger and heavier. Alternatively, it is possible that the comparable direct dive system would be the same size and weight or smaller – in ten years if there are dozens of worm drive table saws or if there is one or none, we will know the answer to this question.

One other consideration is that the motor sees less “slow down resistance” through the gear train, so it may have less of a tendency to bog down. A servo controlled brushless DC motor would tend to resist slow down as well, but I am only aware of brushless motors in battery powered tools at this point. However brushless DC is the next big thing in washing machines and home air conditioning, so perhaps they will make their way to stationary power tools some day.

Also, it should hopefully be apparent why horsepower equals torque (in ft-lbs) multiplied by RPM / 5252 from the above discussing. If I have 100 ft-lbs at 1,000 RPM, it is not as useful to me as 100 ft-lbs at 10,000 RPM. I can gear down the motor spinning at 10,000 RPM by a factor of 10 and get 10 times the torque at the output to my system – ie the motor with 100 ft-lbs at 10,000 RPM can be geared down to produce 1,000 ft-lbs at 1,000 RPM – and that is exactly what happens in the transmission and differential of your car.

This might prove to be an interesting option in the low-priced professional jobsite saw market. Time will tell once folks get to try them out. My experience is that their is no “perfect – one size fits all” jobsite saw that fits everyone’s likes and needs. We had switched over to Bosch 4100 saws and Bosch GCM12SD miter saws both on gravity rise stands, replacing older Makita models. We liked them – but transported them in Step Vans. If we had to transport them in the E-Series Ford vans we used for our plumbing business – we probably would have never bought them based on their weight and bulk.

As Nathan says – a Freud (another Bosch subsidiary) Diablo blade – is probably a step up from the usual junk supplied as standard equipment with most saws, As far as ripping 4x stock on such a small saw – as JMG notes – I too would be cautious – but its nice to have the crosscut ability – if a big miter saw isn’t handy. BTW – we used to use a Makita 5402NA for some timber work – and It was a tool that I personally felt was a bit too big for my 5’8″ – 175lb frame.

I have used both wormdrive and sidewinder style circular saws for years, I have had much much less binding and kickback on cuts with the wormdrive over a sidewinder. I anticipate the same will hold true with this table saw.

I’ve been using a direct drive craftsman for ten years now and while it is reliable (albeit with a terrible fence) this saw may finally force an upgrade.

The real question is how good the fence is. On these portable saws, a fence that stays square is pretty important, since it’s not like you can really upgrade them. I wound up going with the DeWalt DW745 over the Bosch because of the better fence.

If the worm drive actually does anything in terms of power/torque this could be a pretty cool saw, though! It’s nice to see more options on the market.

Hi stuart – Luv your site, I know you try to cover all brands and was wondering if you ever had the chance of doing a review on the top of the line “HITACHI” hammer drill DV18DBL “brushless” {I am happy with mine – they seem to be a solid performer} also have BOSCH brute and MIL 2604. I am sort of a “hitachi” fan and was also hoping that you would do a review on the NEW hatachi “bluetooth” radio model UR18DSALP4………..your response will be greatly appreciated……..victor.